The present invention relates to a process for improving an impact resistance of a shaped article made of hydrolyzed ethylene-vinyl acetate copolymer.
The hydrolyzed ethylene-vinyl acetate copolymer has been used as film, sheet or fiber, but the copolymer has not been employed as yet in the field of the so-called engineering plastics, for instance, electric-device parts such as knob or cabinet or machine parts such as pulley, roller, bar, gear, cam, bobbin or housing, e.g. switch cover, motor cover or transformer cover.
A shaped article made of the hydrolyzed ethylene-vinyl acetate copolymer is excellent in oil resistance, and also far superior in the properties of hardness, tensile strength, flexural strength and compression strength to known thermoplastics, but inferior in impact resistance.
Therefore, such a shaped article has not been employed in the field of an engineering plastics to which high impact strength is often applied.
When a shaped article made of the copolymer is used for an engineering plastics, crack and breakdown often occur, especially in a short period of time after molding.